Automatic back-rest.



G. E.- PETERSON. AUTOMATIC BACK REST.

APPLICATION men APR. 15. |916. Y

Patented July 18, 1916.

IN V EN TOR.

ffy/f GUsTAF E. PETERSON, OF HARTFORD, ooNNEcTIoUT.

\ AUTOMATIC BACK-EEST.

Application led April 15, 1916. Serial No. 91,312.

To alliwhom "it may coarn .'l

Be it known that l, GUsTAF E. PETERSON,

a citizen ofthe United States, residing at Hartford, `in'the county of Hartford and State of Connecticut, have 4invented afnew and useful Improvement in AutomaticvBack- Rests, of which the following is a specification.

This invention relates to those vdevices that are used for supporting or reinforcing stock while being turnedl in a lathe or ground in a grinding machine, which 'devices are known as back rests.

The object lof the invention is to provide a back rest applicable to the common types of lathe, grinder or similar r`machine tool,l

which can be quickly set for stock' of any -diameter within the range of the implement and that will 4automatically adjust itself to the stock and rmly supportit as the size becomes reduced by turningor grinding.

The embodiment of the invention illustrated has a-body with radiallynarranged plungers which .are adjustable in length in order to adapt thedevice to 'be used with stock of various diameters, and that Vare normally thrust outward by springs and when in useare forced inward toward a common center by cams controlled by a weighted level' so that the plungers will automatically follow the stock las it is being reduced in diameter, andtheir inner ends always bear against the surface of the stock with a unil yoke-shaped body 1 hasashank 2 by meansv form pressure sufficiently strong to prevent it from bending or yielding under the action of the cutting or abrading tool.

Of the accompanying drawings Figure 1 is a view looking toward the front edge of the back rest. Fig. 2 shows a side view of the same. Fig. 3 shows a top view. Fig. 4 shows a section on the plane indicated by the dotted line '1L-f4 on Fig. 2. Fig.. 5 is a side view with the plunger-operating cam# plate omitted and one'end of the body Acut in section. Fig. 6 shows a view of the insideof the cam-plate.

ln'the form of the invention shown the of which the implement" may be mounted on the bed of the machine tool with which it is to be used. Infthree radially formed sockets, one at the top, one at the bottom, and one at the back of the body, are plungers, each of which` consists of a retaining sleeve and fa-backing stud 4, the stud be, ing ad]ustab1y held inthe sleeve by a screw Specification of Letters Patent.

Patente I,

lthe sleeve and ,studagainst relative rotary movement. Springs 7 are, arranged in the" sockets to thrust the plungers radially outward.

Turning around on a segmental rib or hub 8 projecting from one side face of the body and retained in place by a (cap plate 9 is an arc-shaped cam'- plate.10. On the inner side of a wall on the inside face of this cam-plate are three cams or wedges 11. These cams are designed to. Overlie the shoulders l2 on oneside ofthe outer'ends of the plunger sleeves. turned one way the cams engage the shoulders on the sleeves and force the plungers uniformly inward,=and when the cam-plate is turned the other waythe Aplungers are pressed outwardly by their springs. vThe cams hold the plungers from rotating and When the cam-plate-is from being thrust out of the sockets by the springs,. and the shoulders against which the cams bear are somewhat inclined or wedge-shaped so there will be an easy engagement between the shoulders and the cams. Attached to the cam-plate is an arm or lever 13 movably held upon which is a c weight 14. When the screw 15 is loosened the weight may be 4moved along the camplate lever. cam-plate so as to force the plungers radially inward towarda common center. spring pin 16 is arranged to projgct a shght distance from the shank of the body beneath the'lever so as to hold vthe weight up when the implement is not being used.

After the piece ofstock to 4be operated 1s located in the heads of the machine, the back rest is moved up into position in the common This weight tends to turn the Y way` and the screws are turned so-that lthe y ends of the plunger' studs will bear' upon the` oft the operatin'gtool; thus no matter howmuch the stock is `'cut down it/ls always rmly supported by this back rest. Q

The invention claimed is;

' 1.- A backfres't having a yoke shaped body,- radially arranged plungers l loo'selysup- PQI'id by the body, means'for varying the supported by the body, means for increasingl length of the plungmers, springs for thrustingthe plungers outward, and a weight for moving the plungers inward.

2. A back rest having a yoke shaped body, radially eXtensible plungers loosely or diminishing the length of the plungers, springs for thrusting the plungers outwardly, a cam plate for forcing the plungers inwardly, and a weight mounted Y, onA and adapted to turn the cam plate.

3. A back resthaving a yoke shaped body, radially arranged plungers loosely supported by the body, means for adjusting the inner `endsvof the plungers independently of the body part of the plungers, springs for thrusting the plungers outwardly, a cam.

and a weight for moving the plungers inward. l

5. A back rest having a yoke-shaped body, radially arranged sleeves loosely supported by the body, studs loosely carried by the sleeves, means for adjusting the studs longitudinally with relation to the sleeves, means for thrusting the sleeves outwardly, and a weight for moving `the sleeves and studs inwardly. v

6. A bao'k rest having a yoke-'shaped body with radially arranged sockets, sleeves loosely mounted in said sockets, studs loosely mounted in said sleeves, ndjusting screws connecting the sleeves and the studs, springs arranged in the sockets for thrusting thesleeves and studsoutward, a cam-plate with cams engaging the outer ends of the sleeves, and a weight adapted to turn the cam-plate Aand force' the sleeves and studs inward.

GUS'IAF E; PETERSON. 

